The present invention relates to seat assemblies and, more particularly, to a support structure for a seat assembly.
Seat assemblies, such as those used in vehicles, generally include a support structure interconnected between a seatback and a seat bottom for strengthening the seat assembly and providing support to an occupant. Many seat assemblies further include a mounting location integrally formed of the support structure for fixedly attaching a seatbelt retractor assembly thereto. Attaching a retractor assembly directly to the support structure of a seat assembly enhances occupant comfort and improves passenger compartment aesthetics. For example, mounting the seatbelt retractor to a seat assembly improves occupant comfort as the relationship of the seatbelt to the occupant remains constant throughout a range of angular adjustments of the seatback relative to the seat bottom. In addition to appearance and occupant comfort, mounting the retractor assembly directly to the seat assembly reduces assembly time and provides manufacturing flexibility. For example, vehicles such as convertibles, which generally do not have an upwardly extending B-pillar, do not include a convenient location on which to mount the retractor assembly, but can be manufactured with a seat assembly having an integrated retractor assembly.
In such an arrangement, the structure of the seat assembly must be of sufficient strength to accommodate the potentially high loads that may be generated as a result of vehicle deceleration from impact, severe braking, or the like. In these situations, the seatback plays a role as many seatbelt assemblies are shoulder mounted requiring mounting on an upper portion of the seatback. Alternatively, some seatbelt assemblies mount the retractor assembly to the seat bottom or other vehicle structure while still routing seatbelt webbing through the seatback to provide a shoulder-type restraint integral with the seatback. In either situation, loading of a shoulder-mounted seatbelt assembly causes a force to be applied at the interface of the seatbelt and the seatback under deceleration of the vehicle.
The force applied to the seatback is typically transmitted through the seatback structure to the seat bottom and ultimately to the structure of the vehicle through a pivotal connection of the seatback and the seat bottom. For shoulder-mounted seatbelt assemblies the force is magnified due to the moment arm extending from the seatback pivot to the point at which the seatbelt loads the seatback. As such, the seatback structure must be strong enough to transmit the generally high loads resulting from vehicle deceleration while also accommodating articulation of the seatback relative to the seat bottom.
Known seat assemblies providing for attachment of a seat belt retractor assembly to a vehicle seat suffer from the disadvantage of not efficiently and effectively transferring deceleration loads received by the seatback to the vehicle structure. More specifically, known designs for structured seat assemblies have been unable to fully retain the operation features demanded by consumers without requiring complex arrangements for pivotally mounting the seatback to the seat bottom. Further, known seat assemblies require a seat structure specific to each application, including design time and tooling for each independent application. While functionally acceptable, these complex arrangements are often weight prohibitive, cost prohibitive, or both.
Therefore, a seat assembly having a structure capable of pivotably supporting a seatback relative a seat bottom while providing enough strength to support a seatbelt assembly and the loads associated therewith is desirable in the industry. Furthermore, providing a seatback structure capable of adjustment and modification for use in various seating applications and varying vehicle seat designs while minimizing design time and tooling investment is also desirable.
Accordingly, the present invention provides a seat assembly with a tunable tie bar including a housing operably supporting the tie bar and a main pivot for interaction with the tie bar under a loading condition. The housing is fixedly attached to a seatback of the seat assembly and includes first and second C-shaped members fixedly joined together to form the housing and provide a space therebetween in which the tie bar is disposed. The housing further includes an extension for receiving the main pivot, whereby the main pivot receives a seat structure from a seat bottom and provides for relative rotation between the seatback and the seat bottom. The tie bar is an elongate support arm having a U-shaped extension and attachment apertures disposed along its length. The tie bar is fixedly attached to the housing and is in engagement with the main pivot, whereby the U-shaped extension reacts against the main pivot to provide the seatback with sufficient strength.
The tie bar is tunable for different seating applications by adjusting the material properties of the bar, varying the stiffness of the bar by varying the number of apertures formed thereon, or by modifying the interaction of the U-shaped extension and the main pivot. As such, the tunable tie bar allows the use of a common housing in various seating applications and does not require design and tooling of a new housing for each application.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.